The hollow circular shelves are heated with steam, and the material enters at the top, and is discharged at the bottom. During the passage through the dryer, it is moved over each shelf by scrapers which are attached to a central shaft.
A machine very widely used in the chemical industry is the atmospheric drum dryer described in Figs. 36 and 36-A. Paper, all kinds of liquids and pastes are dried
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FIG. 34.—Tubular dryer.
FIG. 35.—Continuous plate dryer.
on this machine, which can be arranged either in single or double rolls. The paste is fed to the drum from a tightly fitting trough, and for liquids, the drum either dips into a trough which is filled with this liquid, or the solution is sprayed against the lower part of the drum by pressure. The latter method gives a better distribution of the material, and therefore higher capacity of the dryer. In all cases, the capacity